Alternative Theories Research Articles

Electro-mechanical coupling model and interlaminar stress analysis of laminated plates containing GSR actuator

Due to its remarkable physical features, graphene nanosheets (GPN) are one of the most appealing reinforcing materials for composites. For polyvinylidene fluoride (PVDF), GPN reinforced composites can dramatically increase its piezoelectric and mechanical characteristics. If the interlaminar shear deformation of laminated plates containing uniform graphene sheets reinforced (GSR) smart piezoelectric layer, which material properties vary widely from layer to layer and subjected to electromechanical loading cannot be accurately predicted, the interlaminar stresses may be very high, eventually leading to interlaminar failure. In light of this, an effective mechanoelectrical coupling model for the accurate prediction of interlaminar stress for composite plates contains GSR actuators is developed in present study. Meanwhile, the finite element formulation (FEF) can be substantially simplified due to the expression of transverse shear stress components becoming more succinct. Therefore, by using the suggested electro-mechanical coupling theory, a three-node FEF is easily constructed. The refinement of transverse shear stress prediction in the context of electromechanical coupling can be accomplished through the application of the Reissner mixed variation theory (RMVT). The performance of the recommended plate model will be evaluated using the results derived from three-dimensional (3D) elastic theory and the selected model. By employing the RMVT method, we improve predictions of transverse shear stresses while considering the electromechanical coupling effect. The results from our model are compared with alternative models and 3D elasticity theory, demonstrating its superiority in satisfying the continuity requirements of transverse shear stresses and exhibiting excellent agreement with exact solutions. This validates the accuracy and applicability of our proposed model. Further to that, the prediction of mechanical characteristics for laminated plates with GSR actuators were systematically studied from the thoroughly perspectives of electromechanical load, piezoelectric layer thickness, graphene volume fraction, and some other parameters.

Grave New World

The shift to multipolarity has China and Russia rising to compete against the American hegemonic world order that has dominated the international scene since the end of the Cold War. However, given this competition, Africa has re-emerged as a theatre in which these tensions are unfolding. China, Russia and America are returning to the predatory relationships they engaged in during the Cold War, with African states becoming allies or environments for extraction and exploitation. Economic interest is central to these relationships. These hegemons are building corridors to promote their economic stability through access to lucrative resources and weapons deals, with politically unstable, conflict-ridden and resource-rich African states most susceptible to this fleecing. This paper applies a Marxist geopolitical lens to explain this phenomenon and why alternative theories, namely Neorealism, fail to fully appreciate the internal and multifaceted reasonings for these dynamics

Quantum corrections on geodesic structure and shadow behavior of the Schwarzschild black hole

Point-like singularities of black hole space–times in general theory of relativity (GR) and alternative theories of gravity are one of the controversial issues for decades. One way to remove the central singularity of the Schwarzschild black hole is the Kazakov–Solodukhin (KS) proposal, which takes into account the effects of quantum field theory within the GR framework leading to the KS black hole. On the other hand, the Event Horizon Telescope (EHT) becomes a noteworthy tool for constraining the black hole parameters in gravitational theories. Hence, in this work, we plan to study the null geodesic structure, shadow behavior, energy emission rate, and deflection angle of the KS black hole. Then, we constrain the quantum correction parameter of the KS black hole via EHT data of the M87* supermassive black hole. We observe that increasing the quantum effects in the KS black hole leads to amplification of the shadow size of the KS black hole.

Metaverse: shifting the reality of services

PurposeThis research aims to focus on the impact of the metaverse on services marketing. After reviewing the past, current and anticipated future of the metaverse, the authors offer multiple research opportunities in accordance with theories germane to the services literature.Design/methodology/approachThe current research uses a conceptual approach focused on key service theories and their relevance in the metaverse.FindingsThe metaverse presents a new paradigm of the customer experience, thus providing an opportunity for service researchers to advance this developing field. Further, the potential shortcomings of existing theory are explored, both within and external to services, to discover important areas for service scholars to examine. This results in research opportunities and questions for scholars to pursue as the metaverse continues to develop and shape consumer experiences.Originality/valueTechnological advancements have enabled the service sector to grow and thrive in the metaverse. It is evident that despite the metaverse’s growth, there remains a tremendous amount left to examine. Existing theories need to be reexamined and modified, or alternative theories reviewed to inform service research on the metaverse. Thus, the present research seeks to provide insight into opportunities for theory development by service researchers and identifies important areas of future scholarly work on the metaverse.

Percolation Theories for Quantum Networks.

Quantum networks have experienced rapid advancements in both theoretical and experimental domains over the last decade, making it increasingly important to understand their large-scale features from the viewpoint of statistical physics. This review paper discusses a fundamental question: how can entanglement be effectively and indirectly (e.g., through intermediate nodes) distributed between distant nodes in an imperfect quantum network, where the connections are only partially entangled and subject to quantum noise? We survey recent studies addressing this issue by drawing exact or approximate mappings to percolation theory, a branch of statistical physics centered on network connectivity. Notably, we show that the classical percolation frameworks do not uniquely define the network's indirect connectivity. This realization leads to the emergence of an alternative theory called "concurrence percolation", which uncovers a previously unrecognized quantum advantage that emerges at large scales, suggesting that quantum networks are more resilient than initially assumed within classical percolation contexts, offering refreshing insights into future quantum network design.

Tidal Deformability of Neutron Stars in Scalar-tensor Theories of Gravity

Gravitational waves from compact binary coalescences are valuable for testing theories of gravity in the strong field regime. By measuring neutron star tidal deformability using gravitational waves from binary neutron stars, stringent constraints were placed on the equation of state of matter at extreme densities. Tidal Love numbers in alternative theories of gravity may differ significantly from their general relativistic counterparts. Understanding exactly how the tidal Love numbers change will enable scientists to untangle physics beyond general relativity from the uncertainty in the equation of state measurement. In this work, we explicitly calculate the fully relativistic l ≥ 2 tidal Love numbers for neutron stars in scalar-tensor theories of gravitation. We use several realistic equations of state to explore how the mass, radius, and tidal deformability relations differ from those of general relativity. We find that tidal Love numbers and tidal deformabilities can differ significantly from those in general relativity in certain regimes. The electric tidal deformability can differ by ∼200%, and the magnetic tidal deformability differs by ∼300%. These deviations occur at large compactnesses (C = M/r ≳ 0.2) and vary slightly depending on the equation of state. This difference suggests that using the tidal Love numbers from general relativity could lead to significant errors in tests of general relativity using the gravitational waves from binary neutron star and neutron star black hole mergers.

Radicalizing Managers’ Climate Education: Getting Beyond the Bull**** Fairy Tale of Eternal Economic Growth

In this essay, I argue that we should radicalize managerial climate change education given that incremental and accommodative forms of responsible management learning and education (RMLE) are at odds with the urgency, nature, and magnitude of the climate crisis. I argue for three practices to radicalize RMLE, and illustrate them through examples from a degrowth context. First, management educators should engage in anti-paradigmatic performative politics to disrupt the reality-making of climate damaging theories, and “realize” better alternative theories. Second, as management educators, we should engage ourselves, our students, and wider stakeholders in anti-paradigmatic thought that transcends and challenges problematic mainstream management paradigms. Third, we should explore what and how we and our students can learn from radical climate movements’ civil disobedience, in order to disrupt climate-damaging practices. In this paper, I aim to provoke and facilitate urgently needed discussions about the radicalization of RMLE for climate change education and beyond. Therefore, I close this essay with an invitation for rejoinders and suggest salient implications for educational practitioners and researchers.

Cosmological singularities in f(T,ϕ)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$f(T,\\phi ) $$\\end{document} gravity

The pursuit of understanding the mysteries surrounding dark energy has sparked significant interest within the field of cosmology. While conventional approaches, such as the cosmological constant, have been extensively explored, alternative theories incorporating scalar field-based models and modified gravity have emerged as intriguing avenues. Among these, teleparallel theories of gravity, specifically the f(T,ϕ)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$f(T,\\phi )$$\\end{document} formulation, have gained prominence as a means to comprehend dark energy within the framework of teleparallelism. In this study, we investigate two well-studied models of teleparallel dark energy and examine the presence of cosmological singularities within these scenarios. Using the Goriely–Hyde procedure, we examine the dynamical systems governing the cosmological equations of these models. Our analysis reveals that both models exhibit Type IV singularities, but only for a limited range of initial conditions. These results could indicate a potential edge for teleparallel cosmological models over their other modified gravity counterparts, as the models we examine seem to be only allowing for weak singularities that too under non general conditions.

Constraining the cosmological model of modified f(Q) gravity: Phantom dark energy and observational insights

Abstract Despite the significant accomplishments of general relativity, numerous unresolved issues persist in our understanding of the cosmos. One of the most perplexing challenges is the ongoing accelerated expansion of the Universe, which continues to elude a complete explanation. Consequently, scientists have proposed various alternative theories to general relativity in pursuit of a deeper understanding. In our analysis, we delve into the recently proposed modified f(Q) gravity, where Q represents the nonmetricity scalar responsible for gravitational effects. Specifically, we investigate a cosmological model characterized by the functional form f(Q) = Q + αQn, where α (with α ≠ 0) and n serve as free parameters. Utilizing this functional form, we construct our Hubble rate, incorporating a specific equation of state to describe the cosmic fluid. Furthermore, we leverage a dataset consisting of 31 data points from Hubble measurements and an additional 1048 data points from the Pantheon dataset. These data serve as crucial constraints for our model parameters, and we employ the Markov Chain Monte Carlo (MCMC) method to explore the parameter space and derive meaningful results. With our parameter values constrained, our analysis yields several noteworthy findings. The deceleration parameter suggests a recent accelerated phase in the cosmic expansion. In addition, the EoS parameter paints a portrait of dark energy exhibiting phantom-like characteristics. Furthermore, we delve into the application of cosmological diagnostic tools, specifically the statefinder and the Om(z) diagnostics. Both of these tools align with our previous conclusions, confirming the phantom-like behavior exhibited by our cosmological model. These results collectively contribute to our understanding of the dynamic interplay between gravity, dark energy, and the expanding cosmos.

An epistemology for democratic citizen science.

More than ever, humanity relies on robust scientific knowledge of the world and our place within it. Unfortunately, our contemporary view of science is still suffused with outdated ideas about scientific knowledge production based on a naive kind of realism. These ideas persist among members of the public and scientists alike. They contribute to an ultra-competitive system of academic research, which sacrifices long-term productivity through an excessive obsession with short-term efficiency. Efforts to diversify this system come from a movement called democratic citizen science, which can serve as a model for scientific inquiry in general. Democratic citizen science requires an alternative theory of knowledge with a focus on the role that diversity plays in the process of discovery. Here, we present such an epistemology, based on three central philosophical pillars: perspectival realism, a naturalistic process-based epistemology, and deliberative social practices. They broaden our focus from immediate research outcomes towards cognitive and social processes which facilitate sustainable long-term productivity and scientific innovation. This marks a shift from an industrial to an ecological vision of how scientific research should be done, and how it should be assessed. At the core of this vision are research communities that are diverse, representative, and democratic.

A clarification on prevailing misconceptions in unimodular gravity

The traditional presentation of Unimodular Gravity (UG) consists on indicating that it is an alternative theory of gravity that restricts the generic diffeomorphism invariance of General Relativity. In particular, as often encountered in the literature, unlike General Relativity, Unimodular Gravity is invariant solely under volume-preserving diffeomorphisms. That characterization of UG has led to some confusion and incorrect statements in various treatments on the subject. For instance, sometimes it is claimed (mistakenly) that only spacetime metrics such that |det gμν | = 1 can be considered as valid solutions of the theory. Additionally, that same (incorrect) statement is often invoked to argue that some particular gauges (e.g. the Newtonian or synchronous gauge) are not allowed when dealing with cosmological perturbation theory in UG. The present article is devoted to clarify those and other misconceptions regarding the notion of diffeomorphism invariance, in general, and its usage in the context of UG, in particular.

Exploring new subclass of k-inflation: Tachyon inflation in [formula omitted] gravity model

It is explained that any scalar field in f(R,T) gravity model could present a new subclass of the k-essence model for inflation. While the case of the quintessence has been studied, there is an empty gap required to be filled by investigating more types of field models. Here, we are aiming to partially fill the gap and concentrate on the tachyon field. In this study, we explore the phenomenon of tachyon inflation in the context of the alternative gravity theory f(R,T)=R+ηT. By applying slow-roll approximations, we examine the model in detail for three different potentials: power-law, generalized T-mode, and inverse hyperbolic cosh. Using observational data and Python coding, we determine a range of values for the model’s free parameters that allow it to fit the data perfectly. In essence, this study provides a comprehensive analysis of tachyon inflation in the R+ηT gravity theory, offering new insights into this alternative framework and its potential to explain tachyon inflation.

“As safe as possible”: a qualitative study of opioid withdrawal and risk behavior among people who use illegal opioids

BackgroundOpioid withdrawal is a regular occurrence among many people who use illicit opioids (PWUIO) that has also been shown to increase their willingness to engage in risk-involved behavior. The proliferation of fentanyl in the illicit opioid market may have amplified this relationship, potentially putting PWUIO at greater risk of negative health outcomes. Understanding the relationship between withdrawal and risk-involved behavior may also have important implications for the ways that problematic drug use is conceptualized, particularly in disease models of addiction, which position risk behavior as evidence of pathology that helps to justify ontological distinctions between addicts and non-addicts. Examining withdrawal, and its role in PWUIO’s willingness to engage in risk, may aid in the development of alternative theories of risk involvement and create discursive spaces for de-medicalizing and de-othering people who use illegal drugs.MethodsThis article is based on 32 semi-structured interviews with PWUIO in the New York City area who also reported recent withdrawal experience. Interviews were conducted remotely between April and August 2022 and recorded for later transcription. Data were then coded and analyzed based on a combination of inductive and deductive coding strategies and informed by the literature.ResultsParticipants described a strong relationship between withdrawal and their willingness to engage in risk-involved behavior that was exacerbated by the proliferation of fentanyl. Yet, their descriptions did not align with narratives of risk as a product of bad decisions made by individuals. Rather, data demonstrated the substantial role of social and structural context, particularly drug policies like prohibition and criminalization, in the kinds of risks that PWUIO faced and their ability to respond to them.ConclusionsWithdrawal should be taken more seriously both from an ethical perspective and as an important catalyst of risk behavior. However, theories that position activities taken to avoid withdrawal as irrational and as evidence of pathology are poorly aligned with the complexity of PWUIO’s actual lives. We recommend the use of less deterministic and less medicalized theories of risk that better account for differences between how people view the world, and for the role of socio-structural forces in the production of risk.

Methods Of Resolving Mukhtalif Hadith Perspective Of Imam Al-Shafi'i

This article recognizes the necessity of dealing with the reality of contradictory traditions and the need for theoretical solutions to resolve them. This is where Imam al-Shafi'i initiated and came up with alternative theories that can be used to solve the irregularities and resolve the incongruity of the traditions that seem to contradict each other. This study aims to find out the methods used by Imam Shafi'i in his resolution of mukhtalif traditions. The method used is descriptive-qualitative. This type of research is literature research. The results of this study indicate that there are several stages of theory and methodology used by Imam al-Shafi'i in resolving mukhtalif traditions consisting of the Jammu wa al-taufiq method, the naskh method, the target method, and tawaqquf. In detail, the Jammu wa taufiq method is further classified by solving through the usual fiqh approach, contextual understanding, correlative understanding, and by the take method. In addition, a settlement model was also found in the problem of tanawwu' al-ibadah. Knowing these details can be used as a basis for thinking in resolving traditions that are assumed to contradict each other. So that the substance

A Severe Challenge to the Modified Newtonian Dynamics Phenomenology in Our Galaxy

Modified Newtonian dynamics (MOND) is one of the most popular alternative theories of dark matter to explain the missing mass problem in galaxies. Although it remains controversial regarding MOND as a fundamental theory, MOND phenomenology has been shown to widely apply in different galaxies, which poses challenges to the standard Lambda cold dark matter model. In this article, we derive analytically the galactic rotation curve gradient in the MOND framework and present a rigorous analysis to examine the MOND phenomenology in our Galaxy. By assuming a benchmark baryonic disk density profile and two popular families of MOND interpolating functions, we show for the first time that the recent discovery of the declining Galactic rotation curve in the outer region (R ≈ 17–23 kpc) can almost rule out the MOND phenomenology at more than 5σ. This strongly supports some of the previous studies claiming that MOND is neither a fundamental theory nor a universal description of galactic properties.

Using social practice theory to examine parenting: A scoping review

Practice theory-based research has been established theoretically as an answer to health and social problems, but its use in empirical research is still emerging. We conducted a scoping review in accordance with JBI guidelines for evidence synthesis to identify methodological characteristics of practice theory-based research concerning parenting. A total of 2681 abstracts were identified, with 214 retained for full text screening. A total of 33 articles were included in the review. The included studies in the review focussed on a range of practices relating to parenting including meal preparation and cooking, mobility and transport, homework and school engagement. Major findings from this scoping review identified the use of multiple methods to draw on different aspects of practice and a high variety of time frames for data collection. The tailoring of practice theory approaches was highly varied, and some studies also combined practice theory with alternate theory and concepts. The results reveal significant diversity in the use of social practice theory, the range of methodological approaches used and the application of a high variety of methods. All studies used some form of interview to investigate practices and ethnography was a main methodological approach adopted. Across the studies there were recommendations for expanding sampling and recruitment strategies. Given the call to adopt new approaches to parenting and child development research, our review serves as a mapping of the multitude of ways practice theory-based research can provide can be used to examine parenting.

Brain-inhabiting bacteria and neurodegenerative diseases: the “brain microbiome” theory

Controversies surrounding the validity of the toxic proteinopathy theory of Alzheimer’s disease have led the scientific community to seek alternative theories in the pathogenesis of neurodegenerative disorders (ND). Recent studies have provided evidence of a microbiome in the central nervous system. Some have hypothesized that brain-inhabiting organisms induce chronic neuroinflammation, leading to the development of a spectrum of NDs. Bacteria such as Chlamydia pneumoniae, Helicobacter pylori, and Cutibacterium acnes have been found to inhabit the brains of ND patients. Furthermore, several fungi, including Candida and Malassezia species, have been identified in the central nervous system of these patients. However, there remains several limitations to the brain microbiome hypothesis. Varying results across the literature, concerns regarding sample contamination, and the presence of exogenous deoxyribonucleic acids have led to doubts about the hypothesis. These results provide valuable insight into the pathogenesis of NDs. Herein, we provide a review of the evidence for and against the brain microbiome theory and describe the difficulties facing the hypothesis. Additionally, we define possible mechanisms of bacterial invasion of the brain and organism-related neurodegeneration in NDs and the potential therapeutic premises of this theory.

An experiment on the link between risk preferences and the willingness to become a farmer

AbstractThis study investigates the link between risk preferences of agricultural students and their willingness to become a farmer. We conducted an incentivized experiment with 577 students of an agricultural university in Indonesia. Discriminating between alternative theories of decision‐making under risk, we find that students' risk preferences behave in accordance with cumulative prospect theory, but risk preferences are not predictive of students' willingness to become a farmer. Framing the experimental lottery task in either an agricultural or a general entrepreneurship context does not alter the predictive power for the willingness to become a farmer. Our results contribute to the debates on risk and farm generational renewal, as well as the (lack of) parallelism in behavioral field experiments.

Power-Based Typology of Marketing Systems: Foundation for Alternative Marketing Theory in the Post-Capitalist Marketing Era

To date, orthodox marketing has regarded markets and marketing systems as static and mechanistic rather than dynamic and emergent under the aegis of neoclassical economics. Nevertheless, today, as we transition to a post-industrial era, multiple marketing systems coexist to create consumer satisfaction. This paper, synthesizing Follett's power dichotomy with Alderson's systems approach, aims to typologize marketing systems from a political economic paradigm, which stresses the importance of power phenomena in developing an alternative marketing theory. The present paper also aims to contribute to theory from a higher-order perspective by integrating various phenomena (i.e., marketing systems and power), which have previously been addressed in a piecemeal fashion across diverse domains. The author proposes the “power-with oriented marketing system” as the ideal marketing system, which aims to facilitate resource transfers and the fair distribution of co-created value in a prosumption disposed, post-capitalist marketing era.

Trajectories of Bright Stars and Shadows around Supermassive Black Holes as Tests of Gravity Theories

General relativity (GR), created more than a century ago, has been checked in various experimental and observational tests. At an early stage of its development, GR predictions were tested in problems where the gravitational field is weak and relativistic corrections can be considered as small perturbations of the Newtonian theory of gravity. However, in recent years due to the progress of new technologies it turned out to be possible to verify the predictions of GR in the limit of a strong gravitational field, as it was done to verify predictions about the profile of the X-ray line of iron Kalpha , estimates of the gravitational wave signal during the mergers of binary black holes and/or neutron stars and during the reconstruction of the shadows of black holes in Sgr A* and M87*. Groups of astronomers using the Keck and VLT (GRAVITY) telescopes confirmed the GR predictions for the redshift of the spectral lines of the S2 star near the passage of its pericenter (these predictions were done in the first post-Newtonian approximation). It is expected that in the near future, observations of bright stars using large telescopes VLT (GRAVITY), Keck, E-ELT and TMT will allow us to verify the predictions of GR in the strong gravitational field of supermassive black holes. Observations of bright stars in the vicinity of the Galactic Center and reconstructions of the shadows of black holes allow not only to verify the predictions of the GR, but also to obtain restrictions on alternative theories of gravity.